JP5913051B2 - In-pipe water immersion type ultrasonic flaw detector - Google Patents

Description

  The present invention relates to an in-pipe insertion water immersion type ultrasonic flaw detector inserted into a pipe.

An in-pipe water immersion type ultrasonic flaw detector inserted into a pipe is used for, for example, inspection of thinning or cracking of a boiler pipe used in a heat exchanger of a boiler.
For example, an in-pipe water immersion type ultrasonic flaw detector disclosed in Patent Document 1 is configured to move in a pipe by a water flow formed by a water pump. Specifically, the ultrasonic flaw detector has a waterproof structure and a flexible shaft arranged on the same axis, and the ultrasonic probe is held by the waterproof structure. A parachute and a disk are attached to the waterproof structure at the most downstream in the water flow direction, and the ultrasonic flaw detector moves smoothly in the pipe without using a cable by receiving the water flow pressure on the parachute and the disk. Can do.

JP 2011-75384 A

  It is desirable that the moving speed of the in-pipe water immersion type ultrasonic flaw detection apparatus is substantially constant in relation to the ultrasonic flaw detection inspection. However, the piping has a portion (small diameter portion) having a small inner diameter, such as a bend portion and a welded portion, in addition to a portion having a normal inner diameter (large diameter portion) such as a straight portion. When the size of the parachute or the disk is set in accordance with the moving speed at the large diameter portion, the moving speed may be slowed or the movement may be stopped when the ultrasonic flaw detector is caught on the small diameter portion.

  Accordingly, an object of the present invention is to provide an in-pipe immersion type ultrasonic flaw detector that can move in a pipe at a substantially constant speed by a water flow.

  According to the present invention, in an in-pipe water immersion type ultrasonic flaw detector configured to move in a pipe by a water flow, a probe having a front guide disposed on the front side in the moving direction and an ultrasonic probe A child unit, at least one waterproof container that houses an electric circuit electrically connected to the ultrasonic probe, and coaxially connecting the front guide, the probe unit, and the waterproof container, At least one of two elastically deformable flexible shafts, a centering tool for arranging the front unit, the probe unit, and the waterproof container at the center in the radial direction of the pipe, and the flexible shaft A propulsion device mounted on the flexible shaft, and the propulsion device is slidable on the flexible shaft. An intermediate portion having a movable boss to be fitted, an end portion fixed to the fixed boss and the movable boss, and capable of projecting toward the radially outer side of the flexible shaft as the movable boss approaches the fixed boss A plurality of wires having an inner peripheral portion surrounding the flexible shaft, and an outer peripheral portion fixed to an intermediate portion of the wire, and the intermediate portion of the wire protrudes outward in the radial direction of the shaft Accordingly, there is provided an in-pipe water immersion type ultrasonic flaw detection apparatus characterized by having a pressure receiving member capable of increasing the pressure receiving area for receiving the water flow.

  According to this configuration, when the ultrasonic flaw detector is caught in a small-diameter portion such as a bend portion or a welded portion and moves late with respect to the water flow or stops, the relative speed with the water flow increases. The pressure from the water flow received by the pressure receiving member increases. For this reason, the pressure receiving area of the pressure receiving member is increased, and the pressure receiving member is in an open state or an expanded state. As the pressure receiving area increases, the pressure from the water flow acting on the pressure receiving member increases, and the propulsive force acting on the flexible shaft increases. As a result of the increased propulsive force, the moving speed of the ultrasonic flaw detector is increased even if the ultrasonic flaw detector is caught at the bend or weld and the moving speed decreases or stops moving.

  When the moving speed increases, the relative speed with the water flow decreases, and the pressure received by the pressure receiving member from the water flow decreases. When the pressure receiving member changes from the closed state to the open state, the pressure receiving member opens toward the radially outer side of the flexible shaft against the elastic force of the wire, and when the pressure decreases, the pressure receiving member is moved by the elastic force of the wire. Is closed or reduced. When the pressure receiving member is in a closed state or a contracted state, the pressure receiving area is reduced, so that the propulsive force acting on the flexible shaft is reduced. For this reason, the moving speed of the ultrasonic flaw detector does not exceed the original moving speed and is stabilized at the original moving speed.

  The wire may be made of resin, and the propulsion device may further include a metal wear-resistant member attached to an intermediate portion of the wire.

Preferably, the wire extends spirally around the flexible shaft.
In this configuration, each wire extends spirally around the flexible shaft, and the length of the wire can be increased as compared with the case where the wire extends along the axis of the flexible shaft. For this reason, even if the space | interval of a fixed ring and a movable ring in a free state is short, when the movable ring moves toward a fixed ring, the protrusion amount of the intermediate part of a wire can be enlarged. As a result, the amount of change in the pressure receiving area of the pressure receiving member can be increased, and the moving speed can be quickly increased when the pressure receiving member spreads.

  According to the present invention, an in-pipe water immersion type ultrasonic flaw detector that can move in a pipe at a substantially constant speed by a water flow is provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically showing an in-pipe water immersion type ultrasonic flaw detection system according to an embodiment of the present invention together with a boiler pipe to be inspected. FIG. 2 is a diagram schematically showing an in-pipe water immersion type ultrasonic flaw detector in FIG. 1. It is a figure which shows schematically the structure of the electric circuit which the in-tube insertion water immersion type ultrasonic flaw detector of FIG. 2 has. It is a side view which shows schematic structure of the propulsion apparatus in FIG. It is a schematic front view of the propulsion device seen from the direction of arrow V in FIG. It is a schematic side view for demonstrating the function of the propulsion apparatus of FIG. It is a schematic side view for demonstrating the function of the propulsion apparatus of FIG. FIG. 7 is a schematic cross-sectional view taken along the line VIII-VIII in FIG. 6. FIG. 8 is a schematic cross-sectional view taken along line IX-IX in FIG. 7. It is a figure which shows schematically the structure of the measurement control unit in FIG. It is a figure which shows an example of the content which the flaw detection apparatus position display part in FIG. 10 displays. It is a flowchart which shows roughly the procedure of the inspection method of a boiler pipe | tube using the in-pipe insertion water immersion type ultrasonic flaw detection system of FIG. It is a flowchart which shows roughly the procedure of the position calculation display method of an ultrasonic flaw detector which the measurement control unit of FIG. 10 performs. It is a figure which shows roughly the in-tube insertion water immersion type ultrasonic flaw detection system which concerns on other one Embodiment of this invention with the boiler pipe | tube of a test object.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in the embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples. Absent.

FIG. 1 shows an in-pipe water immersion type ultrasonic flaw detection system (hereinafter also simply referred to as flaw detection system) according to an embodiment of the present invention, together with a boiler pipe 4 constituting a heat exchanger 2 of a boiler to be inspected. It is a figure which shows a structure schematically.
The boiler tube 4 includes a plurality of straight portions (straight tube portions) 6 and a bend portion (curved tube portion) 8 that connects the straight portions 6 to each other. For example, the straight portions 6 extend in the horizontal direction and are separated from each other in the vertical direction.

  The flaw detection system supplies an in-pipe insertion water immersion type ultrasonic flaw detector (hereinafter also simply referred to as flaw detector) 10 inserted into the boiler tube 4 and water for moving the flaw detector 10 to the boiler tube 4. Water supply system 100.

[Flaw detection equipment]
FIG. 2 is a diagram schematically showing the appearance of the flaw detection apparatus 10. The flaw detection apparatus 10 is a cableless ultrasonic flaw detection apparatus inserted into the boiler tube 4. While moving in the boiler tube 4 by the water flow formed by the water supply system 100, the ultrasonic wave is irradiated toward the inner peripheral surface of the boiler tube 4 and the reflected wave of the ultrasonic wave is received. By analyzing the intensity or waveform of the received reflected wave, it is possible to detect abnormalities such as thinning and cracking in the boiler tube 4.

The flaw detection apparatus 10 includes a probe unit 12, a pulse unit 14, a PC unit 16, a power supply unit 18, a plurality of flexible shafts 20, a plurality of aligning tools 22, a front guide 24, and a rear guide. 26 and one propulsion device 28.
The front guide 24, the power supply unit 18, the PC unit 16, the pulse unit 14, the probe unit 12, and the rear guide 26 are coaxially arranged by the flexible shaft 20 in this order in the moving direction of the boiler tube 4. Connected.

  The probe unit 12 includes at least one ultrasonic probe 30 and a cylindrical probe holder 32 that holds the ultrasonic probe 30. Each ultrasonic probe 30 irradiates ultrasonic waves toward the boiler tube 4 when a pulse signal is applied, and receives a reflected wave reflected by the boiler tube 4. Then, the ultrasound probe 30 outputs a received signal according to the intensity or waveform of the received reflected wave.

  The probe unit 12 has, for example, twelve ultrasonic probes 30, and the twelve ultrasonic probes 30 are probed by shifting the position of the probe holder 32 in the axial direction. They are arranged at intervals of 30 degrees in the circumferential direction of the child holder 32. In this case, the boiler tube 4 can be inspected at 30 ° intervals in the circumferential direction of the boiler tube 4.

Each of the pulse unit 14, the PC unit 16, and the power supply unit 18 includes a waterproof container 34 and a predetermined electric circuit accommodated in the waterproof container 34. In the present embodiment, the flaw detection apparatus 10 has three units, but the number of units is not limited to this.
The waterproof container 34 is made of a material that is lighter than water, such as PP (polypropylene) resin, and has a hollow cylindrical shape. The waterproof container 34 can confine air inside together with the electric circuit, and the flaw detection device 10 can move in a floating state due to the buoyancy of the waterproof container 34.

FIG. 3 shows the configuration of the electric circuit of the flaw detector 10. The pulse unit 14 includes a pulse circuit 40 including a pulse generator 36 and a pulse receiver 38 in a waterproof container 34. The pulse generator 36 generates a pulse signal and applies the pulse signal to the ultrasonic probe 30, and the pulse receiver 38 receives and amplifies the reception signal output from the ultrasonic probe 30. .
Note that the pulse circuit 40 has a plurality of channels according to the number of the ultrasonic probes 30, and can apply a pulse signal to each ultrasonic probe 30 and receive and amplify the received signal.

The PC unit 16 includes an electric circuit (control circuit 47) including an A / D conversion unit 42, a storage unit 44, and a control unit 46 in the waterproof container 34. The A / D converter 42 converts the reception signal amplified by the pulse receiver 38 into digital reception data. The storage unit 44 accumulates the reception data converted by the A / D conversion unit 42. The PC unit 16 may not include the A / D conversion unit 42, and the storage unit 44 may store the amplified received signal as analog data.
The reception data stored in the storage unit 44 can be read by an external information processing apparatus, and an abnormality in the boiler tube 4 can be detected by analyzing the reception data using the external information processing apparatus.

  The control unit 46 controls the entire flaw detection apparatus 10. For example, the control unit 46 controls transmission of a pulse signal by the pulse circuit 40 and writing of received data to the storage unit 44.

  The power supply unit 18 includes an electric circuit (power supply circuit 51) including a booster circuit 48 and a battery 50 in the waterproof container 34. The booster circuit 48 distributes the power of the battery 50 to the pulse circuit 40 and the A / D conversion unit 42, the storage unit 44, and the control unit 46 of the PC unit 16. The power supply circuit 51 may include a power switch that turns on / off the supply of power from the battery 50.

  The flexible shaft 20 is formed of a flexible material such as soft rubber such as PVC. In addition, an ultrasonic probe 30 and a pulse circuit are provided inside the flexible shaft 20 that connects the probe unit 12 and the pulse unit 14, the pulse unit 14 and the PC unit 16, and the PC unit 16 and the power supply unit 18, respectively. 40, an electric wire is inserted for electrical connection between the control circuit 47 and the power supply circuit 51.

  Each alignment tool 22 includes a ring fixed to the flexible shaft 20 and a brush extending radially outward from the ring. In the present embodiment, the alignment tool 22 is provided on each side of the probe unit 12, the pulse unit 14, the PC unit 16, and the power supply unit 18. The aligning tool 22 is configured such that the tip of the brush is in sliding contact with the inner peripheral surface of the boiler tube 4, and the probe unit 12, the pulse unit 14, the PC unit 16, and the power supply unit 18 are connected to the boiler tube 4. It has a function of being positioned approximately in the center in the radial direction.

  The front guide 24 and the rear guide 26 have a surface formed by a smooth curved surface, and are configured so as not to be caught on the inner peripheral surface of the bend portion 8. For example, the front guide 24 and the rear guide 26 are made of a spherical resin.

  The front guide 24 has a guide function for determining the traveling direction of the flaw detection apparatus 10. When the front guide 24 reaches the bend portion 8, the front guide 24 slides with the inner peripheral surface of the bend portion 8, and the traveling direction of the front guide 24 gradually changes according to the curvature of the bend portion 8. Then, following the change in the traveling direction of the front guide 24, the flexible shaft 20 following the front guide 24 also bends gradually.

[Propulsion device]
The propulsion device 28 is attached to the flexible shaft 20 that connects the front guide 24 and the power supply unit 18, and has a function of applying a water flow to the flaw detection device 10 in the boiler tube 4. That is, the propulsion device 28 is attached to the front flexible shaft 20 in the traveling direction.
4 and 5 schematically show the configuration of the propulsion device 28. The propulsion device 28 includes a fixed ring 52, a movable ring 54, a plurality of wires 56, a stopper 58, and a pressure receiving member 60.

The fixing ring 52 is made of, for example, metal, and is fixedly fitted to the flexible shaft 20. The movable ring 54 is made of, for example, metal, and is fitted to the flexible shaft 20 so as to be movable in the axial direction of the flexible shaft 20.
The stopper 58 is made of, for example, a ring-shaped metal, and is fixedly fitted to the flexible shaft 20 at a position separated from the fixing ring 52. The stopper 58 is located between the fixed ring 52 and the movable ring 54, and the minimum distance between the fixed ring 52 and the movable ring 54 is defined by the stopper 58.

  The plurality of wires 56 have elasticity and are made of, for example, a resin such as nylon or a metal. Each of the plurality of wire rods 56 has both end portions fixed to the fixed ring 52 and the movable ring 54, and an intermediate portion of the wire rod 56 bulges outward in the radial direction of the flexible shaft 20.

  The plurality of wire rods 56 are arranged at equal intervals in the circumferential direction of the fixed ring 52 and the movable ring 54, and constitute a generally spherical or oval (egg-shaped) elastically deformable cage 57 as a whole. Yes. In this embodiment, each wire 56 is spirally twisted around the flexible shaft 20, and the positions of both ends of the wire 56 are shifted from each other in the circumferential direction of the flexible shaft 20.

  The pressure receiving member 60 is made of, for example, a sheet-shaped or film-shaped rubber or fiber, and directly or indirectly at an inner peripheral portion fixed directly or indirectly to the flexible shaft 20 and an intermediate portion of each wire 56. It has a fixed outer periphery.

  In the present embodiment, for example, a sleeve 62 made of metal is fixedly fitted to the flexible shaft 20 between the fixing ring 52 and the stopper 58. The inner peripheral portion of the pressure receiving member 60 is fixed to the outer periphery of the sleeve 62, and is fixed to the flexible shaft 20 via the sleeve 62.

  In the present embodiment, for example, a ball made of metal is attached to the intermediate portion of each wire 56 as the wear resistant member 64. The outer peripheral portion of the pressure receiving member 60 is fixed to the wear-resistant member 64, and is fixed to an intermediate portion of each wire 56 via the wear-resistant member 64. The wear-resistant member 64 is configured not to slide on the inner peripheral surface of the straight portion 6 while passing through the straight portion 6. However, in the small-diameter portion such as the bend portion 8 or the welded portion, the wear-resistant member 64 has a small diameter. May abut against the inner peripheral surface of the part.

  6, 7, 8, and 9 are diagrams for explaining the function of the propulsion device 28. 6, 7, 8, and 9, the wire 56 may extend in an arc shape along the axis of the flexible shaft 20.

  6 and 8 show a case where the flaw detection apparatus 10 is moving smoothly in the boiler tube 4 in accordance with the water flow. In this case, the pressure from the water flow received by the pressure receiving member 60 is relatively small, and the area (pressure receiving area) of the pressure receiving member 60 is small when viewed in the axial direction of the boiler pipe 4. In other words, in this state, the pressure receiving member 60 is in a closed state or a narrow state. Even in this closed state, the pressure received by the pressure receiving member 60 acts as a driving force on the flexible shaft 20 via the sleeve 62, the wire 56 and the fixing ring 52.

  7 and 9 show a case where the flaw detection apparatus 10 is caught by a small diameter portion such as the bend portion 8 or a welded portion, and moves late with respect to the water flow or stops. In this case, the pressure from the water flow received by the pressure receiving member 60 increases as the relative speed with the water flow increases. For this reason, the pressure receiving area of the pressure receiving member 60 is increased, and the pressure receiving member 60 is in an open state or an expanded state. As the pressure receiving area increases, the pressure from the water flow acting on the pressure receiving member 60 increases, and the propulsive force acting on the flexible shaft 20 increases. As a result of the increased propulsive force, even if the flaw detection device 10 is caught by the bend portion 8 or the welded portion and the movement speed decreases or stops moving, the movement speed of the flaw detection device 10 increases.

  When the moving speed increases, the relative speed with the water flow decreases, and the pressure received by the pressure receiving member 60 from the water flow decreases. When the pressure receiving member 60 changes from the closed state to the open state, the pressure receiving member 60 opens while expanding the cage 57 toward the radially outer side of the flexible shaft 20 against the elastic force of the wire 56. The pressure receiving member 60 is closed by the elastic force of the wire 56. When the pressure receiving member 60 is in a closed state, the pressure receiving area is reduced, so that the propulsive force acting on the flexible shaft 20 is reduced. For this reason, the moving speed of the flaw detection apparatus 10 does not exceed the original moving speed, and is stabilized at the original moving speed.

  When the pressure receiving member 60 is opened, the movement of the movable ring 54 in the direction toward the fixed ring 52 is limited by the stopper 58, thereby preventing the wire 56 from being excessively bent. In the state where the movable ring 54 is in contact with the stopper 58, the intermediate portion of the wire 56 protrudes most radially outward of the flexible shaft 20. Even in this state, the intermediate portion of the wire 56 is the aligning tool 22. It is designed not to protrude more. That is, the propulsion device 28 does not have a centering function.

  Thus, in the flaw detection apparatus 10 including the propulsion device 28, the pressure receiving area of the pressure receiving member 60 changes according to the change in the movement speed of the flaw detection apparatus 10, and as a result, the movement speed is kept substantially constant.

  In this embodiment, each wire 56 extends spirally around the flexible shaft 20, and the length of the wire 56 can be increased as compared with the case where the wire 56 extends along the axis of the flexible shaft 20. it can. For this reason, even if the space | interval of the fixed ring 52 and the movable ring 54 in a free state is short, the protrusion amount of the intermediate part of the wire 56 in the state which the movable ring 54 contact | abutted to the stopper 58 can be enlarged. . As a result, the amount of change in the pressure receiving area of the pressure receiving member 60 can be increased, and the moving speed can be quickly increased when the pressure receiving member 60 expands.

[Water supply system]
Next, the water supply system 100 for supplying water to the boiler pipe 4 will be described.
The water supply system 100 includes a tank 101 that stores water, a pump 102 that sucks and discharges water in the tank 101 and generates a water flow, a flow rate adjustment unit 104 that can adjust the amount of water supplied to the boiler pipe 4, It has a launch unit 106 for inserting the flaw detection apparatus 10 into the boiler tube 4 and a measurement control unit 108 for controlling the flow rate adjustment unit 104.

[Flow adjustment unit]
The flow rate adjusting unit 104 has four water supply pipes 110 and one boost pipe 112 connected in parallel to the discharge port of the pump 102. Each water supply pipe 110 is provided with an open / close valve (flow rate adjusting valve) 114, and the boost pipe 112 is provided with an open / close valve (boost valve) 116.
The outlets of the four water supply pipes 110 and the boost pipe 112 are connected to the inlets of one supply pipe 118.

[Launch Unit]
The launch unit 106 includes a launch tube 119 and a bypass tube 120. The inlets of the launch pipe 119 and the bypass pipe 120 can be connected to the outlet of the supply pipe 118 via the one-touch coupler 121. The one-touch coupler 121 includes a male connector 122 and a female connector 124, and the male connector 122 can be attached to and detached from the female connector 124.

  The outlets of the launch tube 119 and the bypass tube 120 are connected in parallel to the lower end of the boiler tube 4. The launch tube 119 is connected to the lower end of the boiler tube 4 via the on-off valve 126. The launch tube 119 has, for example, substantially the same inner diameter as the boiler tube 4, and the on-off valve 126 is, for example, a full bore valve having substantially the same inner diameter as the boiler tube 4 and the launch tube 119 when the valve is opened. The bypass pipe 120 is provided with an opening / closing valve 128.

  The flaw detection apparatus 10 is inserted into the launch tube 119 through the female connector 124 with the male connector 122 removed. Then, after connecting the female connector 124 to the male connector 122, supplying water into the launch tube 119 and opening the on-off valve 126, the flaw detector 10 enters the boiler tube 4.

[Measurement control unit]
The measurement control unit 108 includes a plurality of sensors and a measurement control device 129 that is electrically connected to each sensor. FIG. 10 schematically shows the configuration of the measurement control unit 108. The measurement control unit 108 includes a flow rate sensor 130, an inlet side ultrasonic sensor 131, an outlet side ultrasonic sensor 132, and a plurality of microphones 134. Have

The flow rate sensor 130 is a sensor for detecting the supply state of water to the boiler tube 4 and detects the amount of water supplied to the boiler tube 4. In the present embodiment, the flow sensor 130 is provided in the vicinity of the lower end of the boiler pipe 4.
The entrance-side ultrasonic sensor 131 is provided in the vicinity of the lower end of the boiler tube 4 and detects the entry of the flaw detection apparatus 10 into the boiler tube 4, in other words, the start of inspection. In the present embodiment, the inlet side ultrasonic sensor 131 is attached to the outer peripheral surface of the launch tube 119.
The outlet side ultrasonic sensor 132 is provided in the vicinity of the upper end of the boiler tube 4 and detects the arrival of the flaw detector 10, in other words, the end of the inspection.

  The microphone 134 is provided in the vicinity of the bend unit 8, and detects sound generated when the flaw detection apparatus 10 passes through the bend unit 8. The arrival of the flaw detector 10 at the bend unit 8 or the passage of the bend unit 8 of the flaw detector 10 can be detected based on the detected sound.

  The measurement control device 129 is configured by a computer, for example, and is configured by a CPU (Central Processing Unit), a memory, an external storage device, an interface, a monitor, and the like. The measurement control device 129 has a flaw detection device position calculation unit 136, a flaw detection device position display unit 138, and a flow rate control unit 140 in terms of functions.

The flaw detector position calculation unit 136 obtains the position of the flaw detector 10 in the boiler tube 4 based on signals from the flow sensor 130, the inlet side ultrasonic sensor 131, the outlet side ultrasonic sensor 132, and the microphone 134.
Basically, when the flaw detection device position calculation unit 136 detects the entry into the boiler tube 4 by the inlet-side ultrasonic sensor 131, the flaw detection device position calculation unit 136 determines the flaw detection device position calculation unit 136 based on the flow rate of water detected by the flow sensor 130. The moving speed is estimated, and the position of the flaw detector 10 is obtained by calculation based on the moving speed. In the present embodiment, the flaw detector position calculation unit 136 obtains the position of the flaw detector 10 on the assumption that the flow rate of water is equal to the moving speed of the flaw detector 10.

  In addition, when the flaw detection device position calculation unit 136 detects the arrival of the flaw detection device 10 at the bend unit 8 using the microphone 134, the position (calculation position) of the flaw detection device 10 obtained by calculation so as to match the detection result. ) Is corrected.

The flaw detection device position display unit 138 is constituted by, for example, a liquid crystal monitor, and displays the calculation position of the flaw detection device 10 calculated by the flaw detection device position calculation unit 136 as shown in FIG. When the calculation position is corrected based on the detection result of the microphone 134, the flaw detector position display unit 138 displays the corrected calculation position.
The operator can visually recognize the position of the flaw detection apparatus 10 on the flaw detection apparatus position display unit 138.

  The flow controller 140 controls the opening / closing of the flow regulating valve 114 and the boost valve 116 based on signals from the flow sensor 130 and the microphone 134. The flow rate adjustment valve 114 is opened in stages so that the flow rate does not gradually decrease as the flaw detection apparatus 10 progresses. For example, when the flaw detector 10 enters the boiler tube 4, only one flow rate adjustment valve 114 is opened, and the other three flow rate adjustment valves 114 are closed. Each time the flaw detection apparatus 10 passes through the straight portion 6 of the boiler tube 4 in two stages, one flow rate adjustment valve 114 is additionally opened.

  On the other hand, the boost valve 116 is normally closed and is opened when the flow rate is suddenly reduced, and is closed after a predetermined time has elapsed or after the flow rate is restored. The case where the flow rate is rapidly decreased is, for example, a case where the flow rate is reduced exceeding a preset change rate, and the change rate is a change amount of the flow rate per unit time.

  Hereinafter, a method for inspecting the boiler tube 4 using the water supply system 100 and the flaw detection apparatus 10 will be described. The inspection includes a pre-process for acquiring data and a post-process for analyzing the acquired data. Here, the pre-process will be described.

FIG. 12 is a flowchart schematically showing the procedure of the inspection method.
First, the supply pipe 118 is connected to the bypass pipe 120, and water is circulated in the boiler pipe 4 (S10). Thereby, bubbles in the boiler tube 4 are removed so that ultrasonic flaw detection is performed smoothly. Next, the flaw detection apparatus 10 is activated (S12) and placed in the launch tube 119. When the flaw detection apparatus 10 is activated, it starts irradiating ultrasonic waves and recording received data. Then, the supply pipe 118 is connected to the launch pipe 119, the on-off valve 126 is opened, and the flaw detection apparatus 10 is inserted into the boiler pipe 4 (S14).

  While the flaw detector 10 advances in the boiler tube 4 and performs inspection, the flow rate is repeatedly measured substantially continuously (S16), and the flow rate is adjusted according to the measurement result (S18). When the flaw detection apparatus 10 reaches the upper end of the boiler tube 4 and is recovered (S20), the flaw detection apparatus 10 is stopped (S22). Then, the acquired received data is transferred to the information processing apparatus for analysis (S24), and the previous process ends.

  The acquired reception data includes the time and the intensity of the reflected wave at the time for each channel. The information processing apparatus can use, for example, the passage time of the bend unit 8 detected by the microphone 134 when converting the time into the position in the boiler tube 4. In this case, the average speed can be calculated by dividing the distance between the bend units 8 where the microphones 134 are installed by the difference in the passing time of each bend unit 8, and the position can be calculated based on the average speed.

Next, the position calculation and display method (position calculation display method) of the flaw detection apparatus 10 executed by the measurement control device 129 will be described.
FIG. 13 schematically shows the procedure of the position calculation display method. Note that information related to the shape of the boiler tube 4 is input to the measurement control device 129.
First, the measurement control device 129 acquires the insertion time of the flaw detection device 10 based on the signal from the entrance-side ultrasonic sensor 131 (S30). For example, the fact that the flaw detector 10 is present at the inlet of the boiler tube 4 is displayed on the flaw detector position display unit 138.

  Then, the measurement control device 129 repeatedly and substantially continuously acquires the signal from the flow sensor 130 (S32), calculates the position of the flaw detector 10 based on the acquired signal, and displays the calculated position of the flaw detector position. This is displayed on the part 138 (S34). For example, the measurement control device 129 can calculate the position on the assumption that the flow rate of water is equal to the moving speed of the flaw detection device 10.

When the measurement control device 129 detects that the flaw detection device 10 has reached the bend unit 8 by the microphone 134 (S36), the measurement control device 129 corrects the calculated position and displays the corrected position (S38).
The measurement control device 129 repeatedly calculates and displays the position while correcting the calculation position every time it passes through the bend unit 8. When the exit ultrasonic sensor detects that the flaw detection device 10 has reached the upper end of the boiler tube 4 (recovered) (S40), the execution of the position calculation display method is stopped.

  According to the water supply system 100 described above, when the flow rate (velocity) rapidly decreases, the movement speed of the flaw detection apparatus 10 is decreased or the movement is stopped by opening the boost valve and increasing the flow rate. However, the moving speed of the flaw detection apparatus 10 can be recovered. For this reason, according to this water supply system 100, the moving speed of the flaw detection apparatus 10 in the boiler pipe 4 can be kept substantially constant, and the inspection by the flaw detection apparatus 10 can be accurately performed.

The present invention is not limited to the above-described embodiments, and includes forms obtained by modifying the above-described embodiments.
For example, the measurement control unit 108 may have a sound wave sensor (AE sensor) or an ultrasonic sensor instead of the microphone 134. The AE sensor is brought into direct contact with the outer periphery of the boiler tube 4 and detects sound waves generated when the front guide 24 and the aligning tool 22 come into contact with the inner peripheral surface of the boiler tube 4. Detect position. The ultrasonic sensor is brought into direct contact with the outer peripheral surface of the boiler tube 4, radiates ultrasonic waves toward the boiler tube 4, and receives ultrasonic reflected waves. In the case of an ultrasonic sensor, the position of the flaw detector 10 can be detected by receiving the reflected wave reflected by the flaw detector 10.

  As shown in FIG. 14, the measurement control unit 108 may have an inlet side pressure sensor 142 and an outlet side pressure 144 sensor instead of the flow rate sensor 130. In this case, the measurement control device 129 determines the pressure of water on the lower end side of the boiler pipe 4 detected by the inlet side pressure sensor 142 and the pressure of water on the upper end side of the boiler pipe 4 detected by the outlet side pressure sensor 144. The flow rate can be adjusted based on the pressure difference.

Specifically, when the pressure difference increases beyond a predetermined value, the boost valve 116 is opened to increase the flow rate, and after a certain time has elapsed, or after the pressure difference has decreased, the boost valve 116 is turned on. It can be closed to restore the flow.
In this case, the flow rate adjustment valve 114 can be opened and closed according to the vertical position or travel distance of the flaw detection apparatus 10 based on a signal from the microphone 134, an elapsed time since the insertion of the flaw detection apparatus 10, or the like.

  In this way, by opening and closing the boost valve 116 based on the pressure difference between the inlet side and the outlet side of the boiler tube 4, the flow rate is accurately adjusted when the moving speed of the flaw detector 10 decreases or the movement stops. Can be increased. As a result, the moving speed of the ultrasonic flaw detector 10 can be reliably made substantially constant.

In addition, the flaw detection apparatus 10 and the water supply system 100 described above are preferably used in combination, but the flaw detection apparatus 10 may be used in combination with another water supply system, or the water supply system 100 may be combined with another flaw detection apparatus. You may use it in combination.
Finally, the flaw detection apparatus 10 and the water supply system 100 are suitable for the inspection of the boiler pipe 4, but it is needless to say that the flaw detection apparatus 10 and the water supply system 100 can also be applied to inspection of piping for other uses.

2 Heat exchanger 4 Boiler tube (pipe)
6 Straight part 8 Bend part 10 In-pipe water immersion type ultrasonic flaw detector 12 Probe unit 14 Pulse unit 16 PC unit 18 Power supply unit 20 Flexible shaft 22 Alignment tool 24 Front guide 26 Rear guide 28 Propeller 30 Over Acoustic wave probe 32 Probe holder 34 Waterproof container 47 Control circuit 48 Booster circuit 51 Power supply circuit 52 Fixed ring 54 Movable ring 56 Wire material 57 Cage 58 Stopper 60 Pressure receiving member 62 Sleeve 64 Wear resistant member

Claims (3)

In the pipe insertion water immersion type ultrasonic flaw detector configured to move in the pipe by water flow,
A front guide arranged on the front side in the moving direction;
A probe unit having an ultrasonic probe;
At least one waterproof container containing an electric circuit electrically connected to the ultrasonic probe;
At least two elastically deformable flexible shafts that coaxially connect the front guide, the probe unit, and the waterproof container;
An alignment tool for disposing the front unit, the probe unit, and the waterproof container at the radial center of the pipe;
A propulsion device attached to at least one of the flexible shafts,
The propulsion device is
A fixed boss that is fixedly fitted to the flexible shaft;
A movable boss slidably fitted to the flexible shaft;
A plurality of wire rods having both ends fixed to the fixed boss and the movable boss, and having an intermediate portion capable of projecting toward the radially outer side of the flexible shaft as the movable boss approaches the fixed boss;
An inner peripheral portion surrounding the flexible shaft and an outer peripheral portion fixed to the intermediate portion of the wire rod, and the water flow as the intermediate portion of the wire rod projects outward in the radial direction of the shaft. receiving area for receiving is closed and capable of receiving member increases,
In the advancing direction of the water immersion type ultrasonic flaw detector inserted in the tube, the movable boss is located behind the fixed boss ,
The tube insertion water immersion type ultrasonic flaw detection apparatus, wherein the pressure receiving area of the pressure receiving member changes according to a change in the moving speed of the tube insertion water immersion type ultrasonic flaw detection apparatus. The wire is made of resin,
The in-pipe water immersion type ultrasonic flaw detector according to claim 1, wherein the propulsion device further includes a metal wear-resistant member attached to an intermediate portion of the wire.   The in-pipe water immersion type ultrasonic flaw detector according to claim 1, wherein the wire extends spirally around the flexible shaft.

Images